Horizontal joint for a rotary machine and method of assembling same

ABSTRACT

A horizontal joint of a rotary machine barrel includes first and second section mating surfaces that extend axially adjacent to the joint, and a plurality of gaps and a plurality of tangs disposed axially along the first and second section mating surfaces, respectively. Each tang has an axially extending tang aperture defined therethrough. Each gap is sized and axially spaced to receive a corresponding tang. Additionally, the joint includes a plurality of mating surface segments defined along the first section mating surface. Each segment extends axially between a corresponding pair of gaps and has an axially extending segment aperture defined therethrough. The tang apertures and segment apertures align to form a generally continuous axial pin aperture when the second section mating surface is positioned against the first section mating surface.

BACKGROUND

The field of the disclosure relates generally to a horizontal joint for a rotary machine, and more particularly to a rotary machine horizontal joint coupled together by an axial pin.

At least some known rotary machines, such as some known gas turbines, include a generally tubular inner barrel that circumscribes a rotor assembly, and a generally tubular outer barrel that circumscribes the inner barrel. A gas flow path may be defined in a generally annular space between the inner and outer barrels. Moreover, in at least some such rotary machines, an upper section and a lower section of the inner barrel and/or an upper section and a lower section of the outer barrel are coupled together along a pair of horizontal joints that extend axially along opposing sides of the inner barrel. The upper and lower sections each include a flange that extends along each horizontal joint. A plurality of bolt holes are defined at cooperating locations in each upper and lower flange, and bolts may be installed in these joint flange bolt holes to couple the sections together.

In at least some known horizontal joints, the horizontal joint flanges and joint flange bolts are located on an interior, radially inner side of the inner barrel to facilitate shielding the flanges and bolts from the gas flow path. However, for maintenance activities that require the bolts to be inspected or removed, personnel typically must enter the interior of the inner barrel to access the bolts. The interior of the inner barrel typically presents a difficult workspace in which to maneuver, increasing a time required for maintenance and a cost. In addition, a minimum diameter of the inner barrel that is necessary to facilitate personnel entry into the interior may be larger than a diameter that is necessary to satisfy operational requirements for the rotary machine. Therefore, a need to facilitate personnel entry into the interior of the inner barrel may increase a size and manufacturing cost of the rotary machine.

BRIEF DESCRIPTION

In one aspect, a horizontal joint for coupling a first section and a second section of a barrel of a rotary machine is provided. The horizontal joint includes a first section mating surface that extends axially along the first section adjacent to the horizontal joint, and a second section mating surface that extends axially along the second section adjacent to the horizontal joint. The horizontal joint also includes a plurality of tangs disposed axially along the second section mating surface. Each tang of the plurality of tangs has an axially extending tang aperture defined therethrough. The horizontal joint further includes a plurality of gaps disposed axially along the first section mating surface. Each gap of the plurality of gaps is sized and axially spaced to receive a corresponding one of the tangs. Additionally, the horizontal joint includes a plurality of mating surface segments defined along the first section mating surface. Each mating surface segment of the plurality of mating surface segments extends axially between a corresponding adjacent pair of the plurality of gaps, and each mating surface segment has an axially extending segment aperture defined therethrough. The tang apertures and the segment apertures are configured to align to form a generally continuous axial pin aperture when the second section mating surface is positioned against the first section mating surface.

In another aspect, an exhaust frame for a rotary machine is provided. The exhaust frame includes a first section of an inner barrel. The first section includes a first section mating surface that extends axially along the first section adjacent to a horizontal joint of the inner barrel. The exhaust frame also includes a second section of the inner barrel. The second section includes a second section mating surface that extends axially along the second section adjacent to the horizontal joint. The second section mating surface is positioned against the first section mating surface. The exhaust frame further includes a plurality of tangs disposed axially along the second section mating surface. Each tang of the plurality of tangs has an axially extending tang aperture defined therethrough. Additionally, the exhaust frame includes a plurality of gaps disposed axially along the first section mating surface. Each tang is received within a corresponding one of the gaps. Also, the exhaust frame includes a plurality of mating surface segments defined along the first section mating surface. Each mating surface segment of the plurality of mating surface segments extends axially between a corresponding adjacent pair of the plurality of gaps, and each mating surface segment has an axially extending segment aperture defined therethrough. The tang apertures and the segment apertures align to form a generally continuous axial pin aperture, and an axial pin is positioned in the axial pin aperture.

In yet another aspect, a method of assembling an exhaust frame for a rotary machine is provided. The exhaust frame includes an inner barrel that has a first section and a second section. The method includes positioning a first section mating surface of the first section against a second section mating surface of the second section. The first section mating surface extends axially along the first section adjacent to a horizontal joint of the inner barrel, and the second section mating surface extends axially along the second section adjacent to the horizontal joint. The method also includes receiving each tang of a plurality of tangs within a corresponding gap of a plurality of gaps. The plurality of tangs is disposed axially along the second section mating surface. The plurality of gaps is disposed axially along the first section mating surface. The method further includes aligning a plurality of tang apertures and a plurality of segment apertures to form a generally continuous axial pin aperture. Each tang aperture extends axially through a corresponding tang, and each segment aperture extends axially through a corresponding mating surface segment. Each mating surface segment extends axially between a corresponding adjacent pair of the plurality of gaps. Additionally, the method includes positioning an axial pin in the axial pin aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary gas turbine;

FIG. 2 is a simplified perspective view of an exemplary first section and an exemplary second section of an exhaust frame that may be used with the exemplary gas turbine shown in FIG. 1;

FIG. 3 is a schematic cross-section of an exemplary horizontal joint for coupling the first section and the second section shown in FIG. 2;

FIG. 4 is a simplified perspective view of the first section and second section shown in FIG. 2 coupled together to form an exemplary exhaust frame that may be used with the exemplary gas turbine shown in FIG. 1;

FIG. 5 is a schematic cross-section of the horizontal joint shown in FIG. 3 coupled together; and

FIG. 6 is a flow chart of an exemplary method of assembling an exhaust frame for a rotary machine, such as the exemplary gas turbine shown in FIG. 1.

DETAILED DESCRIPTION

The exemplary methods and systems described herein overcome at least some of the disadvantages associated with known horizontal joints for barrels of rotary machines. The embodiments described herein include a horizontal joint secured by an axial pin. The axial pin may be installed and removed in a barrel horizontal joint without a need for personnel to enter the interior of the barrel, and thus facilitates assembly, disassembly, and maintenance of the rotary machine.

FIG. 1 is a schematic view of an exemplary gas turbine 10 in which embodiments of the inner barrel of the current disclosure may be used. While FIG. 1 describes an exemplary gas turbine engine, it should be noted that the barrel horizontal joints described herein are not limited to any one particular type of rotary machine. One of ordinary skill in the art will appreciate that the current methods and systems described herein may be used with any rotary machine, including a steam turbine, in any suitable configuration that enables such methods and systems to operate as further described herein.

In the exemplary embodiment, gas turbine 10 includes an intake section 12, a compressor section 14 coupled downstream from intake section 12, a combustor section 16 coupled downstream from compressor section 14, a turbine section 18 coupled downstream from combustor section 16, and an exhaust section 20 coupled downstream from turbine section 18. A casing 36 at least partially encloses one or more of intake section 12, compressor section 14, combustor section 16, turbine section 18, and exhaust section 20. Casing 36 may include a plurality of casings that at least partially enclose different sections of gas turbine 10.

Turbine section 18 is coupled to compressor section 14 via a rotor shaft 22. It should be noted that, as used herein, the term “couple” is not limited to a direct mechanical, electrical, and/or communication connection between components, but may also include an indirect mechanical, electrical, and/or communication connection between multiple components. In the exemplary embodiment, rotor shaft 22 is at least partially supported by a forward bearing assembly 30 (sometimes referred to as an “N1 bearing assembly”) and an aft bearing assembly 32 (sometimes referred to as an “N2 bearing assembly”).

During operation of gas turbine 10, intake section 12 channels air towards compressor section 14. Compressor section 14 compresses the air to a higher pressure and temperature and discharges the compressed air towards combustor section 16. In combustor section 16, the compressed air is mixed with fuel and ignited to generate combustion gases that are channeled towards turbine section 18. More specifically, combustor section 16 includes at least one combustor 24, in which a fuel, for example, natural gas and/or fuel oil, is injected into the air flow, and the fuel-air mixture is ignited to generate high temperature combustion gases that are channeled towards turbine section 18.

Turbine section 18 converts the thermal energy from the combustion gas stream to mechanical rotational energy, as the combustion gases impart rotational energy to at least one rotor blade 38 coupled to rotor shaft 22 within turbine section 18. Rotor shaft 22 may be coupled to a load (not shown) such as, but not limited to, an electrical generator and/or a mechanical drive application. The exhausted combustion gases flow downstream from turbine section 18 into exhaust section 20. In the exemplary embodiment, aft bearing assembly 32 is at least partially disposed within exhaust section 20, and exhaust section 20 is at least partially supported and/or formed by an exhaust frame 100. In an embodiment, exhaust frame 100 at least partially forms a section of casing 36.

FIG. 2 is a simplified perspective view of an exemplary embodiment of a first section 108 and a second section 110 positioned to be coupled together to form an exemplary embodiment of exhaust frame 100 (shown in FIG. 4). First section 108 includes an inner barrel first section 112 and an outer barrel first section 180, and second section 110 includes an inner barrel second section 140 and an outer barrel second section 182. Inner barrel first section 112 is coupled to outer barrel first section 180, and inner barrel second section 140 is coupled to outer barrel second section 182, by a plurality of circumferentially spaced struts 106. Moreover, inner barrel first section 112 and inner barrel second section 140 are configured to be coupled together by an axially extending pin 116 at each of a pair of oppositely disposed, axially extending inner barrel horizontal joints 114. Outer barrel first section 180 and outer barrel second section 182 are configured to be coupled together at each of a pair of oppositely disposed, axially extending outer barrel horizontal joints 184.

FIG. 3 is a schematic cross-section of an embodiment of one of the inner barrel horizontal joints 114 positioned for coupling first section 112 and second section 140, taken along line 3-3 shown in FIG. 2. Inner barrel second section 140 includes a mating surface 150 that extends axially along inner barrel second section 140 adjacent to joint 114. A plurality of tangs 142 is disposed axially along second section 140 adjacent to joint 114. In the illustrated embodiment, each tang 142 extends generally vertically from mating surface 150 of second section 140. Each tang 142 has a tang thickness 144 and is separated from an adjacent tang 142 by a separation distance 146. In the exemplary embodiment, each tang 142 has an equal tang thickness 144 and the separation distance 146 between each tang 142 is equal. In alternative embodiments, at least one tang 142 has a tang thickness 144 that differs from the tang thickness 144 of another tang 142, and/or at least one tang 142 has a separation distance 146 from an adjacent tang 142 that differs from the separation distance 146 between another pair of adjacent tangs 142.

Each tang 142 has an axially extending tang aperture 148 defined therethrough. Each tang aperture 148 is centered around a second centerline 152 and has a second diameter 154. In the exemplary embodiment, although second diameter 154 is constant within a given tang aperture 148, second diameter 154 decreases from a maximum value in the tang 142 adjacent to a pin insertion end 156 of joint 114, to a minimum value in the tang 142 adjacent to a pin tip end 158 of joint 114. This decrease in second diameter 154 along the plurality of tangs 142 accommodates a correspondingly tapered shape of axial pin 116 (shown in FIG. 5), which facilitates ease of insertion of axial pin 116 into joint 114 from pin insertion end 156. In alternative embodiments, second diameter 154 may vary within a given tang aperture 148, and/or may vary among apertures 148 within different tangs 142 in another suitable fashion. In other alternative embodiments, second diameter 154 is equal for each tang aperture 148 to accommodate a correspondingly non-tapered shape of axial pin 116.

Inner barrel first section 112 includes a mating surface 120 that extends axially along inner barrel first section 112 adjacent to joint 114. A plurality of gaps 118 is disposed axially along inner barrel first section 112 adjacent to joint 114. In the illustrated embodiment, each gap 118 extends generally vertically into first section 112 from first section mating surface 120. Additionally, a plurality of mating surface segments 124 is defined along first section mating surface 120 by the plurality of gaps 118. More specifically, each mating surface segment 124 extends axially between a corresponding adjacent pair of the plurality of gaps 118. Each gap 118 is sized and axially spaced to receive a corresponding tang 142 when inner barrel first section mating surface 120 is positioned against inner barrel second section mating surface 150. More specifically, each gap 118 has a width 122 sized to receive tang thickness 144 of a corresponding tang 142 in a clearance fit. Similarly, each mating surface segment 124 has a segment thickness 126 that is sized to be received within separation distance 146 between a corresponding pair of tangs 142 in a clearance fit.

Each mating surface segment 124 has an axially extending segment aperture 128 defined therethrough. Each segment aperture 128 is centered around a first centerline 162 and has a first diameter 164. Similarly to second diameter 154, in certain embodiments, although first diameter 164 is constant within a given segment aperture 128, first diameter 164 decreases from a maximum value in the mating surface segment 124 adjacent to a pin insertion end 156 of joint 114, to a minimum value in the mating surface segment 124 adjacent to a pin tip end 158 of joint 114. This decrease in first diameter 164 along the plurality of mating surface segments 124 accommodates a correspondingly tapered shape of axial pin 116 (shown in FIG. 5), which facilitates ease of insertion of axial pin 116 into joint 114 from pin insertion end 156. In alternative embodiments, first diameter 164 may vary within a given segment aperture 128, and/or may vary among apertures 128 within different mating surface segments 124 in another suitable fashion. In other alternative embodiments, first diameter 164 is equal for each segment aperture 128 to accommodate a correspondingly non-tapered shape of axial pin 116.

In the exemplary embodiment, tangs 142 and gaps 118 cooperate such that first centerline 162 and second centerline 152 align when inner barrel first section mating surface 120 is positioned against inner barrel second section mating surface 150. Moreover, second diameter 154 and first diameter 164 are sized within plurality of tangs 142 and plurality of mating surface segments 124, respectively, such that tang apertures 148 and segment apertures 128 are configured to align to form a generally continuous axial pin aperture 192 (shown in FIG. 5) when inner barrel first section mating surface 120 is positioned against inner barrel second section mating surface 150.

FIG. 4 is a simplified perspective view of first section 108 and second section 110 coupled together to form exhaust frame 100. More specifically, inner barrel first section 112 and inner barrel second section 140 are coupled together to form a generally tubular, axially extending inner barrel 102. Moreover, inner barrel first section 112 and inner barrel second section 140 are secured by respective axial pins 116 inserted from a first axial end 194 of exhaust frame 100 into each inner barrel horizontal joint 114. In addition, outer barrel first section 180 and outer barrel second section 182 are coupled together in any suitable fashion at each outer barrel horizontal joint 184 to form a generally tubular, axially extending outer barrel 104. Inner barrel 102 and outer barrel 104 are coupled together by struts 106 such that outer barrel 104 circumscribes inner barrel 102 in a generally concentric relationship.

In the exemplary embodiment, an annular space 186 defined between inner barrel 102 and outer barrel 104 is configured to accommodate exhausted combustion gases that flow downstream from turbine section 18 (shown in FIG. 1). Moreover, a pair of oppositely disposed bearing supports 188 disposed on inner barrel second section 140 form at least a portion of aft bearing assembly 32 (shown in FIG. 1) in a radially interior space 190 defined within inner barrel 102. Thus, a portion of rotor shaft 22 (shown in FIG. 1) may be disposed within interior space 190.

FIG. 5 is a schematic cross-section of an embodiment of one of the coupled inner barrel horizontal joints 114, taken along line 5-5 shown in FIG. 4. Inner barrel first section mating surface 120 is positioned against inner barrel second section mating surface 150 such that each tang 142 is received within a corresponding one of gaps 118. It should be understood that in some embodiments, at least one layer of material, such as for example a sealant material, may be disposed between first section mating surface 120 and second section mating surface 150 when first section mating surface 120 is positioned against second section mating surface 150. Tang apertures 148 and segment apertures 128 (shown in FIG. 3) align to form generally continuous axial pin aperture 192. Axial pin 116 is positioned in axial pin aperture 192 to secure inner barrel first section 112 and inner barrel second section 140. Because pin insertion end 156 of joint 114 is accessible from first axial end 194 (shown in FIG. 4) of exhaust frame 100, axial pin 116 may be installed and removed without a need for personnel to enter interior space 190 of inner barrel 102.

It should be understood that, while horizontal joint 114 has been described in terms of inner barrel 102 of exhaust frame 100, embodiments of horizontal joint 114 additionally or alternatively may be used at other suitable barrel locations on gas turbine 10 (shown in FIG. 1), such as for example on outer barrel 104 at outer barrel horizontal joint 184, or on inlet section 12 (shown in FIG. 1). It also should be understood that, while first section 108, inner barrel first section 112, and outer barrel first section 180 are the “upper” sections and second section 110, inner barrel second section 140, and outer barrel second section 182 are the “lower” sections in the illustrated embodiment, this is for convenience of description only. In alternative embodiments (not shown), first section 108, inner barrel first section 112, and outer barrel first section 180 are the lower sections and second section 110, inner barrel second section 140, and outer barrel second section 182 are the upper sections, such that plurality of tangs 142 extends from the upper inner barrel section and plurality of gaps 118 is defined in the lower inner barrel section.

An exemplary method 600 of assembling an exhaust frame, such as exhaust frame 100, for a rotary machine, such as gas turbine 10, is illustrated in FIG. 6. With reference also to FIGS. 1-5, the exhaust frame includes an inner barrel, such as inner barrel 102, that has a first section and a second section, such as first section 112 and second section 140. The method includes positioning 602 a first section mating surface, such as mating surface 120, of the first section against a second section mating surface, such as second section mating surface 150, of the second section. The first section mating surface extends axially along the first section adjacent to a horizontal joint of the inner barrel, such as horizontal joint 114, and the second section mating surface extends axially along the second section adjacent to the horizontal joint. Method 600 also includes receiving 604 each tang of a plurality of tangs, such as tangs 142, within a corresponding gap of a plurality of gaps, such as gaps 118. The plurality of tangs is disposed axially along the second section mating surface, and each tang extends generally vertically from the second section. The plurality of gaps is disposed axially along the first section mating surface, and each gap extends generally vertically into the first section.

Method 600 further includes aligning 606 a plurality of tang apertures, such as tang apertures 148, and a plurality of segment apertures, such as segment apertures 128, to form a generally continuous axial pin aperture, such as axial pin aperture 192. Each tang aperture extends axially through a corresponding tang, and each segment aperture extends axially through a corresponding mating surface segment. Each mating surface segment extends axially between a corresponding adjacent pair of the plurality of gaps. Additionally, method 600 includes positioning 608 an axial pin, such as axial pin 116, in the axial pin aperture.

In certain embodiments, receiving 604 each tang within the corresponding gap further comprises receiving 610 a tang thickness, such as tang thickness 144, of each tang within a width, such as width 122, of the corresponding gap in a clearance fit. In addition, receiving 610 the tang thickness may further comprise receiving 612 each tang having an equal tang thickness. Method 600 also may include receiving 614 a segment thickness, such as segment thickness 126, of each mating surface segment within a separation distance, such as separation distance 146, between a corresponding pair of the tangs in a clearance fit.

Moreover, in some embodiments, each segment aperture has a first diameter, such as first diameter 164, each tang aperture has a second diameter, such as second diameter 154, and each of the first diameter and the second diameter decreases from a maximum value adjacent to a pin insertion end, such as pin insertion end 156, of the horizontal joint to a minimum value adjacent to a pin tip end, such as pin tip end 158, of the horizontal joint. Positioning 608 the axial pin may comprise inserting 616 the axial pin having a correspondingly tapered shape into the axial pin aperture. Positioning 608 the axial pin also may comprise inserting 618 the axial pin into the axial pin aperture from a first axial end, such as first axial end 194, of the exhaust frame. Additionally, method 600 may include positioning 620 an outer barrel such that the outer barrel circumscribes the inner barrel in a generally concentric relationship.

Exemplary embodiments of a horizontal joint for use with a rotary machine, and of a method of assembling such a horizontal joint, are described above in detail. The embodiments provide an advantage in enabling assembly and disassembly of the horizontal joint from an axial end of the coupled sections. Thus, the embodiments enable assembly, disassembly, and maintenance of, for example, an exhaust frame inner barrel without a requirement for personnel to enter the interior of the inner barrel. This facilitates a reduction in a time required for maintenance and a corresponding reduction in an outage time of the rotary machine.

The methods and systems described herein are not limited to the specific embodiments described herein. For example, components of each system and/or steps of each method may be used and/or practiced independently and separately from other components and/or steps described herein. In addition, each component and/or step may also be used and/or practiced with other assemblies and methods.

While the disclosure has been described in terms of various specific embodiments, those skilled in the art will recognize that the disclosure can be practiced with modification within the spirit and scope of the claims. Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. Moreover, references to “one embodiment” in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 

What is claimed is:
 1. A horizontal joint for coupling a first section and a second section of a barrel of a rotary machine, said horizontal joint comprising: a first section mating surface that extends axially along the first section adjacent to said horizontal joint; a second section mating surface that extends axially along the second section adjacent to said horizontal joint; a plurality of tangs disposed axially along said second section mating surface, each said tang has an axially extending tang aperture defined therethrough; a plurality of gaps disposed axially along said first section mating surface, each said gap is sized and axially spaced to receive a corresponding one of said tangs; and a plurality of mating surface segments defined along said first section mating surface, each mating surface segment of said plurality of mating surface segments extends axially between a corresponding adjacent pair of said plurality of gaps, each said mating surface segment has an axially extending segment aperture defined therethrough, wherein said tang apertures and said segment apertures are configured to align to form a generally continuous axial pin aperture when said second section mating surface is positioned against said first section mating surface.
 2. The horizontal joint of claim 1, wherein said second section mating surface is positioned against said first section mating surface, further comprising an axial pin inserted into said axial pin aperture.
 3. The horizontal joint of claim 1, wherein each said tang has a tang thickness and each said gap has a width sized to receive said tang thickness of a corresponding one of said tangs in a clearance fit.
 4. The horizontal joint of claim 3, wherein said tang thickness is equal for each said tang.
 5. The horizontal joint of claim 1, wherein each of said tangs is separated from an adjacent one of said tangs by a separation distance, each said mating surface segment has a segment thickness that is sized to be received within the separation distance between a corresponding pair of said tangs in a clearance fit.
 6. The horizontal joint of claim 1, wherein each said segment aperture has a first diameter and each said tang aperture has a second diameter, each of said first diameter and said second diameter decreases from a maximum value adjacent to a pin insertion end of said horizontal joint to a minimum value adjacent to a pin tip end of said joint.
 7. An exhaust frame for a rotary machine, said exhaust frame comprising: a first section of an inner barrel, said first section comprising a first section mating surface that extends axially along said first section adjacent to a horizontal joint of said inner barrel; a second section of said inner barrel, said second section comprising a second section mating surface that extends axially along said second section adjacent to said horizontal joint, said second section mating surface is positioned against said first section mating surface; a plurality of tangs disposed axially along said second section mating surface, each said tang has an axially extending tang aperture defined therethrough; a plurality of gaps disposed axially along said first section mating surface, each said tang is received within a corresponding one of said gaps; a plurality of mating surface segments defined along said first section mating surface, each mating surface segment of said plurality of mating surface segments extends axially between a corresponding adjacent pair of said plurality of gaps, each said mating surface segment has an axially extending segment aperture defined therethrough, wherein said tang apertures and said segment apertures align to form a generally continuous axial pin aperture; and an axial pin positioned in said axial pin aperture.
 8. The exhaust frame of claim 7, wherein each said tang has a tang thickness and each said gap has a width sized to receive said tang thickness of a corresponding one of said tangs in a clearance fit.
 9. The exhaust frame of claim 8, wherein said tang thickness is equal for each said tang.
 10. The exhaust frame of claim 7, wherein each of said tangs is separated from an adjacent one of said tangs by a separation distance, each said mating surface segment has a segment thickness that is sized to be received within the separation distance between a corresponding pair of said tangs in a clearance fit.
 11. The exhaust frame of claim 7, wherein each said segment aperture has a first diameter and each said tang aperture has a second diameter, each of said first diameter and said second diameter decreases from a maximum value adjacent to a pin insertion end of said horizontal joint to a minimum value adjacent to a pin tip end of said joint to accommodate a correspondingly tapered shape of said axial pin.
 12. The exhaust frame of claim 7, further comprising an outer barrel that circumscribes said inner barrel in a generally concentric relationship.
 13. The exhaust frame of claim 12, wherein an annular space is defined between said inner barrel and said outer barrel, said annular space is configured to accommodate exhausted combustion gases that flow downstream from a turbine section of the rotary machine.
 14. A method of assembling an exhaust frame for a rotary machine, the exhaust frame including an inner barrel comprising a first section and a second section, said method comprising: positioning a first section mating surface of the first section against a second section mating surface of the second section, wherein the first section mating surface extends axially along the first section adjacent to a horizontal joint of the inner barrel and the second section mating surface extends axially along the second section adjacent to the horizontal joint; receiving each tang of a plurality of tangs within a corresponding gap of a plurality of gaps, wherein the plurality of tangs is disposed axially along the second section mating surface and the plurality of gaps is disposed axially along the first section mating surface; aligning a plurality of tang apertures and a plurality of segment apertures to form a generally continuous axial pin aperture, wherein each tang aperture extends axially through a corresponding tang and each segment aperture extends axially through a corresponding mating surface segment, and wherein each mating surface segment extends axially between a corresponding adjacent pair of the plurality of gaps; and positioning an axial pin in the axial pin aperture.
 15. The method of claim 14, wherein said receiving each tang within the corresponding gap further comprises receiving a tang thickness of each tang within a width of the corresponding gap in a clearance fit.
 16. The method of claim 15, wherein said receiving the tang thickness of each tang within the width of the corresponding gap further comprises receiving each tang having an equal tang thickness.
 17. The method of claim 14, further comprising receiving a segment thickness of each mating surface segment within a separation distance between a corresponding pair of the tangs in a clearance fit.
 18. The method of claim 14, wherein each segment aperture has a first diameter and each tang aperture has a second diameter, and each of the first diameter and the second diameter decreases from a maximum value adjacent to a pin insertion end of the horizontal joint to a minimum value adjacent to a pin tip end of the horizontal joint, and wherein said positioning the axial pin comprises inserting the axial pin having a correspondingly tapered shape into the axial pin aperture.
 19. The method of claim 14, wherein said positioning the axial pin comprises inserting the axial pin into the axial pin aperture from a first axial end of the exhaust frame.
 20. The method of claim 14, further comprising positioning an outer barrel such that the outer barrel circumscribes the inner barrel in a generally concentric relationship. 